1. Field of the Invention
The present invention relates to a thin sheet-form illumination device for illuminating objects to be illuminated such as images printed on paper, liquid crystal displays, or solid objects, and to a bulletin board device or the like employing an illumination device according to the present invention.
2. Description of the Related Art
As in Early Japanese Patent Publication No. H.6-324331, in a conventional sheet illumination device arranged at the front face of for example a liquid crystal display, the light-guide plate constituting the illumination device consists in a flat plate of high rigidity.
However, since in the conventional sheet illumination devices, the light guide plate was a flat plate of high rigidity, and as the conventional liquid crystal display devices etc. using flat rigid bodies made of for example glass were mostly employed for illumination of planar articles of high rigidity, when they were employed for illumination of objects having curved surfaces or flexibility, irregular spaces were produced between the illumination device and the illuminated object, making uniform illumination difficult to achieve and impairing flexibility of the illuminated object: thus they were sometimes unsuitable for their purpose.